GH-2633 - Be more lenient when mapping DTOs.

src/main/java/org/springframework/data/neo4j/core/mapping/DefaultNeo4jEntityConverter.java

@@ -34,6 +34,7 @@
 import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
 
+import org.neo4j.driver.Record;
 import org.neo4j.driver.Value;
 import org.neo4j.driver.Values;
 import org.neo4j.driver.internal.value.NullValue;
@@ -82,6 +83,8 @@ final class DefaultNeo4jEntityConverter implements Neo4jEntityConverter {
 	private final Type relationshipType;
 	private final Type mapType;
 	private final Type listType;
+	private final Type pathType;
+
 	private final Map<String, Collection<Node>> labelNodeCache = new HashMap<>();
 
 	DefaultNeo4jEntityConverter(EntityInstantiators entityInstantiators, NodeDescriptionStore nodeDescriptionStore,
@@ -101,6 +104,7 @@ final class DefaultNeo4jEntityConverter implements Neo4jEntityConverter {
 		this.relationshipType = typeSystem.RELATIONSHIP();
 		this.mapType = typeSystem.MAP();
 		this.listType = typeSystem.LIST();
+		this.pathType = typeSystem.PATH();
 	}
 
 	@Override
@@ -112,7 +116,7 @@ public <R> R read(Class<R> targetType, MapAccessor mapAccessor) {
 
 		@SuppressWarnings("unchecked") // ¯\_(ツ)_/¯
 		Neo4jPersistentEntity<R> rootNodeDescription = (Neo4jPersistentEntity<R>) nodeDescriptionStore.getNodeDescription(targetType);
-		MapAccessor queryRoot = determineQueryRoot(mapAccessor, rootNodeDescription);
+		MapAccessor queryRoot = determineQueryRoot(mapAccessor, rootNodeDescription, true);
 
 		try {
 			return queryRoot == null ? null : map(queryRoot, queryRoot, rootNodeDescription);
@@ -122,7 +126,7 @@ public <R> R read(Class<R> targetType, MapAccessor mapAccessor) {
 	}
 
 	@Nullable
-	private <R> MapAccessor determineQueryRoot(MapAccessor mapAccessor, @Nullable Neo4jPersistentEntity<R> rootNodeDescription) {
+	private <R> MapAccessor determineQueryRoot(MapAccessor mapAccessor, @Nullable Neo4jPersistentEntity<R> rootNodeDescription, boolean firstTry) {
 
 		if (rootNodeDescription == null) {
 			return null;
@@ -183,9 +187,40 @@ private <R> MapAccessor determineQueryRoot(MapAccessor mapAccessor, @Nullable Ne
 			}
 		}
 
+		// The aggregating mapping function synthesizes a bunch of things and we must not interfere with those
+		boolean isSynthesized = isSynthesized(mapAccessor);
+		if (!isSynthesized) {
+			// Check if the original record has been a map. Would have been probably sane to do this right from the start,
+			// but this would change original SDN 6.0 behaviour to much
+			if (mapAccessor instanceof Value && ((Value) mapAccessor).hasType(mapType)) {
+				return mapAccessor;
+			}
+
+			// This is also due the aggregating mapping function: It will check on a NoRootNodeMappingException
+			// whether there's a nested, aggregatable path
+			if (firstTry && !canBeAggregated(mapAccessor)) {
+				Value value = Values.value(Collections.singletonMap("_", mapAccessor.asMap(Function.identity())));
+				return determineQueryRoot(value, rootNodeDescription, false);
+			}
+		}
+
 		throw new NoRootNodeMappingException(mapAccessor, rootNodeDescription);
 	}
 
+	private boolean canBeAggregated(MapAccessor mapAccessor) {
+
+		if (mapAccessor instanceof Record r) {
+			return r.values().stream().anyMatch(pathType::isTypeOf);
+		}
+		return false;
+	}
+
+	private boolean isSynthesized(MapAccessor mapAccessor) {
+		return mapAccessor.containsKey(Constants.NAME_OF_SYNTHESIZED_ROOT_NODE) &&
+			mapAccessor.containsKey(Constants.NAME_OF_SYNTHESIZED_RELATIONS) &&
+			mapAccessor.containsKey(Constants.NAME_OF_SYNTHESIZED_RELATED_NODES);
+	}
+
 	private Collection<String> createDynamicLabelsProperty(TypeInformation<?> type, Collection<String> dynamicLabels) {
 
 		Collection<String> target = CollectionFactory.createCollection(type.getType(), String.class, dynamicLabels.size());

src/test/java/org/springframework/data/neo4j/integration/lite/A.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2011-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.neo4j.integration.lite;
+
+/**
+ * DTO with nested DTO
+ *
+ * @author Michael J. Simons
+ */
+public class A {
+	private String outer;
+
+	private B nested;
+
+	public String getOuter() {
+		return outer;
+	}
+
+	public void setOuter(String outer) {
+		this.outer = outer;
+	}
+
+	public B getNested() {
+		return nested;
+	}
+
+	public void setNested(B nested) {
+		this.nested = nested;
+	}
+}

src/test/java/org/springframework/data/neo4j/integration/lite/B.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2011-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.neo4j.integration.lite;
+
+/**
+ * Inner DTO
+ *
+ * @author Michael J. Simons
+ */
+public class B {
+	private String inner;
+
+	public String getInner() {
+		return inner;
+	}
+
+	public void setInner(String inner) {
+		this.inner = inner;
+	}
+}

src/test/java/org/springframework/data/neo4j/integration/lite/LightweightMappingIT.java

@@ -0,0 +1,146 @@
+/*
+ * Copyright 2011-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.neo4j.integration.lite;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.Collection;
+import java.util.Optional;
+
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.neo4j.driver.Driver;
+import org.neo4j.driver.Session;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.data.neo4j.core.DatabaseSelectionProvider;
+import org.springframework.data.neo4j.core.transaction.Neo4jBookmarkManager;
+import org.springframework.data.neo4j.core.transaction.Neo4jTransactionManager;
+import org.springframework.data.neo4j.repository.config.EnableNeo4jRepositories;
+import org.springframework.data.neo4j.test.BookmarkCapture;
+import org.springframework.data.neo4j.test.Neo4jExtension;
+import org.springframework.data.neo4j.test.Neo4jImperativeTestConfiguration;
+import org.springframework.data.neo4j.test.Neo4jIntegrationTest;
+import org.springframework.transaction.PlatformTransactionManager;
+import org.springframework.transaction.annotation.EnableTransactionManagement;
+
+@Neo4jIntegrationTest
+class LightweightMappingIT {
+
+	protected static Neo4jExtension.Neo4jConnectionSupport neo4jConnectionSupport;
+
+	@BeforeAll
+	static void setupData(@Autowired Driver driver, @Autowired BookmarkCapture bookmarkCapture) {
+
+		try (Session session = driver.session(bookmarkCapture.createSessionConfig())) {
+			session.run("MATCH (n) DETACH DELETE n").consume();
+			// language=cypher
+			session.run(
+					"""
+							CREATE (u1:User {login: 'michael', id: randomUUID()})
+							CREATE (u2:User {login: 'gerrit', id: randomUUID()})
+							CREATE (so1:SomeDomainObject {name: 'name1', id: randomUUID()})
+							CREATE (so2:SomeDomainObject {name: 'name2', id: randomUUID()})
+							CREATE (so1)<-[:OWNS]-(u1)-[:OWNS]->(so2)
+							"""
+			);
+			bookmarkCapture.seedWith(session.lastBookmarks());
+		}
+	}
+
+	@Test
+	void getAllFlatShouldWork(@Autowired SomeDomainRepository repository) {
+
+		Collection<MyDTO> dtos = repository.getAllFlat();
+		assertThat(dtos).hasSize(10)
+				.allSatisfy(dto -> {
+					assertThat(dto.counter).isGreaterThan(0);
+					assertThat(dto.resyncId).isNotNull();
+				});
+	}
+
+	@Test
+	void getOneFlatShouldWork(@Autowired SomeDomainRepository repository) {
+
+		Optional<MyDTO> dtos = repository.getOneFlat();
+		assertThat(dtos).hasValueSatisfying(dto -> {
+			assertThat(dto.counter).isEqualTo(4711L);
+			assertThat(dto.resyncId).isNotNull();
+		});
+	}
+
+	@Test
+	void getAllNestedShouldWork(@Autowired SomeDomainRepository repository) {
+
+		Collection<MyDTO> dtos = repository.getNestedStuff();
+		assertThat(dtos).hasSize(1)
+				.first()
+				.satisfies(dto -> {
+					assertThat(dto.counter).isEqualTo(4711L);
+					assertThat(dto.resyncId).isNotNull();
+					assertThat(dto.user)
+							.isNotNull()
+							.extracting(User::getLogin)
+							.isEqualTo("michael");
+					assertThat(dto.user.getOwnedObjects())
+							.hasSize(2);
+
+				});
+	}
+
+
+	@Test
+	void getTestedDTOsShouldWork(@Autowired SomeDomainRepository repository) {
+
+		Optional<A> dto = repository.getOneNestedDTO();
+		assertThat(dto).hasValueSatisfying(v -> {
+			assertThat(v.getOuter()).isEqualTo("av");
+			assertThat(v.getNested()).isNotNull()
+					.extracting(B::getInner).isEqualTo("bv");
+		});
+
+	}
+
+	@Configuration
+	@EnableTransactionManagement
+	@EnableNeo4jRepositories(considerNestedRepositories = true)
+	static class Config extends Neo4jImperativeTestConfiguration {
+
+		@Bean
+		public Driver driver() {
+			return neo4jConnectionSupport.getDriver();
+		}
+
+		@Bean
+		public BookmarkCapture bookmarkCapture() {
+			return new BookmarkCapture();
+		}
+
+		@Override
+		public PlatformTransactionManager transactionManager(Driver driver, DatabaseSelectionProvider databaseNameProvider) {
+
+			BookmarkCapture bookmarkCapture = bookmarkCapture();
+			return new Neo4jTransactionManager(driver, databaseNameProvider, Neo4jBookmarkManager.create(bookmarkCapture));
+		}
+
+		@Override
+		public boolean isCypher5Compatible() {
+			return neo4jConnectionSupport.isCypher5SyntaxCompatible();
+		}
+	}
+
+}

src/test/java/org/springframework/data/neo4j/integration/lite/MyDTO.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2011-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.neo4j.integration.lite;
+
+/**
+ * DTO with optionally linked domain object
+ *
+ * @author Michael J. Simons
+ */
+public class MyDTO {
+	String resyncId;
+
+	Long counter;
+
+	User user;
+}

src/test/java/org/springframework/data/neo4j/integration/lite/SomeDomainObject.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2011-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.neo4j.integration.lite;
+
+import java.util.UUID;
+
+import org.springframework.data.neo4j.core.schema.GeneratedValue;
+import org.springframework.data.neo4j.core.schema.Id;
+import org.springframework.data.neo4j.core.schema.Node;
+
+/**
+ * Irrelevant to the tests in this package, but needed for setting up a repository.
+ *
+ * @author Michael J. Simons
+ */
+@Node
+public class SomeDomainObject {
+
+	@Id
+	@GeneratedValue
+	private UUID id;
+
+	private final String name;
+
+	public SomeDomainObject(String name) {
+		this.name = name;
+	}
+
+	public UUID getId() {
+		return id;
+	}
+
+	public String getName() {
+		return name;
+	}
+}